Bacteriuria in a population sample of women. Prevalence, characteristics, results of treatment, and prognosis.

The prevalence of bacteriuria was studied in a population sample of women aged 38-60. Significant (greater than or equal to 100 000 bacteria/ml of the same species in two consecutive specimens) or "probable" bacteriuria (greater than or equal to 100 000 in the first and 20 000-90 000 bacteria/ml of the same organism in the second specimen) were found in 5% of the women, increasing from 3.5% in women aged 38 to 8.6% in women aged 60. Escherichia coli predominated (90% of those with significant bacteriuria), and 91% of the Escherichia coli strains were sensitive to sulphonamides. About half of the women who were non-bacteriuric after short-term treatment had one or more recurrent urinary tract infections during a two-year follow-up period. Serum creatinine and urine concentrating capacity did not differentiate women with significant or "probable" bacteriuria from the others. Pathological radiological changes were found in 17% of bacteriuric women who were submitted to i.v. pyelography. When re-examined six years after the first study, 23% of initially bacteriuric and 5% of initially non-bacteriuric women had bacteriuria. Patients with renal lesions have been followed for ten years, but none of them has developed progressive renal impairment. Three women with chronic pyelonephritis and acute pyelonephritic attacks in the past were discovered when screening the concentrating capacity in this population sample, but they were non-bacteriuric when screening for bacteriuria. A study of this kind must be conducted over many years before valid conclusions can be drawn.